Optical fiber test apparatus with combined light measurement and fault detection

ABSTRACT

An optical fiber test apparatus includes an optical power meter operable to detect light at a predetermined wavelength, and a laser source operable to generate a visible laser beam. The optical fiber test apparatus further includes an optical fiber extending between a first end and a second end, and a diplexer which includes a first optical connector and is coupled to the optical power meter, the laser source, and the first end of the optical fiber. The optical fiber test apparatus further includes a second optical connector coupled to the second end of the optical fiber and including a test port. The diplexer is operable to transmit light at the predetermined wavelength from the second optical connector to the optical power meter and transmit the visible laser beam from the laser source to the second optical connector.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of and claims priority to U.S.patent application Ser. No. 15/381,827 having a filing date of Dec. 16,2016, which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present disclosure relates generally to optical fiber testapparatus, and more particularly to improved test apparatus whichprovide features for both measuring light transmission through opticalfibers and detecting fault locations on the optical fibers.

BACKGROUND OF THE INVENTION

At present it requires three separate instruments to test andtroubleshoot a failed/failing fiber span to determine where the problemmay lie. The first two instruments are an optical power meter (OPM) anda matching optical light source, ‘matching’ defined as the light sourceoperating on wavelengths the OPM is designed to detect and measure. Thethird instrument is a visual fault indicator (VFI) embodied as a visiblelight source, typically a laser emitting in the visible spectrum. If afiber span fails the loss test, one of the two testing instruments mustbe removed and replaced with the visual fault indicator in order tolocate the fault causing the loss test failure.

The use of these separate test instruments is time consuming,cumbersome, and can result in damage to the optical connector on thefiber span under test and/or the test port optical connector.

Accordingly, improved testing apparatus for optical fibers is desired.In particular, testing apparatus that reduce or eliminate therequirement for multiple separate instruments, and that thus reduce theassociated time and risk involved in such testing, would beadvantageous.

BRIEF DESCRIPTION OF THE INVENTION

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In accordance with one embodiment, an optical fiber test apparatus isprovided. The optical fiber test apparatus includes an optical powermeter operable to detect light at a predetermined wavelength, and alaser source operable to generate a visible laser beam. The opticalfiber test apparatus further includes an optical fiber extending betweena first end and a second end. The optical fiber test apparatus furtherincludes a diplexer, the diplexer including a first optical connectorand coupled to the optical power meter, the laser source, and the firstend of the optical fiber. The diplexer is coupled to the first end ofthe optical fiber through the first optical connector. The optical fibertest apparatus further includes a second optical connector coupled tothe second end of the optical fiber and including a test port. Thediplexer is operable to transmit light at the predetermined wavelengthfrom the second optical connector to the optical power meter andtransmit the visible laser beam from the laser source to the secondoptical connector.

These and other features, aspects and advantages of the presentinvention will become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the invention and, together with the description, serveto explain the principles of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 illustrates an optical fiber test apparatus in accordance withone embodiment of the present disclosure;

FIG. 2 illustrates components of an optical fiber test apparatus inaccordance with one embodiment of the present disclosure; and

FIG. 3 illustrates components of an optical fiber test apparatus inaccordance with another embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope or spirit ofthe invention. For instance, features illustrated or described as partof one embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

In general, the present disclosure is directed to optical fiber testapparatus which advantageously provide features for both measuring lighttransmission through optical fibers and detecting fault locations on theoptical fibers. Test apparatus in accordance with the present disclosureinclude both optical power meters and laser sources, and provide novelfeatures for simultaneously connecting an optical power meter and lasersource to an optical fiber to be tested. Accordingly, testing of opticalfibers utilizing test apparatus in accordance with the presentdisclosure will advantageously be more efficient and will reduce therisks associated with the use of separate test instruments for varioustesting requirements. For example, troubleshooting a failed fiber spanwill be made less time consuming. Test apparatus in accordance with thepresent disclosure advantageously eliminate the need for a separatevisible light source, and eliminates the requirement to disconnect theoptical power meter in order to connect a visible light source, in turnreducing the probability of damaging the optical connector on the fiberspan under test and/or the test port optical connector by eliminating anoptical connector/test port disconnect/connect cycle.

Referring now to FIGS. 1 through 3, various embodiments of an opticalfiber test apparatus 10 in accordance with the present disclosure areillustrated. A test apparatus 10 may include, for example, an opticalpower meter 12. The optical power meter 12 is generally operable todetect and measure the power of light at one or more predeterminedwavelengths or ranges of wavelengths. The detected and measured lightis, in exemplary embodiments, light on the infrared wavelength spectrum.Common wavelengths (i.e. those utilized in optical fibers) include 850nanometers, 1300 nanometers, and 1550 nanometers. In general, an opticalpower meter 12 may include a measurement circuit 14. The measurementcircuit 14 may generally convert a received signal for measurementand/or display purposes. For example, the measurement circuit 14 mayconvert a received current into a voltage, and send this voltage to ananalog to digital converter. The resulting digital signal may then bedisplayed as an optical power meter 12 output.

The received current may be converted from received light at aparticular wavelength. For example, in exemplary embodiments, theoptical power meter 12 may further include a photodiode 16 whichgenerally converts received light into current. This current may then,for example, be received by the measurement circuit 14.

Test apparatus 10 may further include a laser source 20. The lasersource 20 may be operable to generate a visible laser beam, i.e. a laserbeam within the visible wavelength spectrum (390 nanometers to 700nanometers, such as in some embodiments 525 nanometers to 700nanometers). In exemplary embodiments, the laser beam may, for example,be green or red. Laser source 20 may, for example, include a laserdriver circuit 22. Laser source 20 may further include a laser diode 24.The laser driver circuit 22 may generally drive the laser diode 24 toproduce a laser beam at a desired wavelength, i.e. a visible wavelength.

The test apparatus 10 may further include an optical connector 30, whichmay be referred to herein as a second optical connector 30. The opticalconnector 30 may include a test port 32. The test port 32 may be a portof the optical connector 30 to which an optical fiber 34 to be testedmay be connected to the optical connector 30. The optical connector 30may in exemplary embodiments be a universal connector interface or an FCconnector (i.e. ferrule connector). Suitable FC connectors may include,for example, FC/UPC and FC/APC connectors. Alternatively, however, othersuitable optical connectors 30 may be utilized.

Notably, the optical fiber 34 to be tested may be a single mode ormulti-mode optical fiber. An optical light source 36 may generate light(i.e. infrared light) at a suitable predetermined wavelength(s) fortransmission through the optical fiber 34 to the test apparatus 10through the optical connector 30 thereof, and through the test apparatus10 to the optical power meter 12 thereof for detection and measurement.

The test apparatus 10 may further include an optical fiber 40 whichextends between a first end 42 and a second end 44. The optical fiber 40may be a single mode or multi-mode optical fiber. In some embodiments, acore of the optical fiber 40 may have a standard diameter, i.e.approximately 50 microns. Alternatively, the diameter of the core of theoptical fiber 40 may be greater than approximately 50 microns. Forexample, in some embodiments the core diameter may be approximately 62.5microns or approximately 100 microns. As utilized herein, approximatelymeans plus or minus 3 microns. The optical fiber 40 may be coupled (suchas directly coupled) at the second end 44 thereof to the opticalconnector 30. The optical fiber 40 may provide for the transmissiontherethrough of light to and from the optical connector 30, and thus toand from the optical fiber 34 being tested. For example, light (i.e.infrared light) at a suitable predetermined wavelength(s) generated byoptical light source 36 may be transmitted (i.e. in direction 100) fromoptical connector 30 to and through optical fiber 40 for transmission tothe optical power meter 12. Additionally, visible laser beams may betransmitted from the laser source 20 to and through the optical fiber 40(i.e. in direction 102), and from the optical fiber 40 through theoptical connector 30 to the optical fiber 34 for, for example, faultdetection purposes.

As shown in FIGS. 2 and 3, the optical fiber 40 may be a component of acable 46 which may include the optical fiber 40 and one or more outerlayers surrounding the optical fiber 40, one of which may include anexterior surface 48 of the cable 46. The first and second ends 42, 44 ofthe optical fiber 40 may protrude beyond the other layers of the cable46 and into suitable optical fiber connectors which facilitateconnection of the optical fiber with the second optical connector 30 anda first optical connector 60 as discussed herein.

Test apparatus 10 may further include a diplexer 50. The diplexer 50 mayallow the transmission of light therethrough, and may direct light (i.e.infrared light) at a suitable predetermined wavelength(s) generated byoptical light source 36 to the optical power meter 12 and visible laserlight from laser source 20 to the optical connector 30 for transmissiontherethrough to the optical fiber 34. Diplexer 50 may thus be coupled(i.e. directly coupled) to the optical fiber 40 at the first end 42thereof.

In general, any suitable diplexer 50 may be utilized in accordance withthe present disclosure. Diplexer 50 may include, for example, a beamsplitter 52, a first lens 54, a second lens 55, and a third lens 56.These components may be contained internally within a body 58 of thediplexer 50. First lens 54 may, for example, be optically alignedbetween the beam splitter 52 and optical fiber 40. Second lens 55 may,for example, be optically aligned between the beam splitter 52 and theoptical power meter 12, such as the photodiode 16 thereof. Third lens 56may, for example, be optically aligned between the beam splitter 52 andthe laser source 20, such as the laser diode 24 thereof.

Any suitable beam splitter 52 may be utilized. For example, in someembodiments, the beam splitter 52 may be a glass, an optical filmcoating, or a cubic. As is generally understood, the beam splitter 52may transmit a portion of light received by the beam splitter 52therethrough, and may reflect another portion of the received light.Further, any suitable lenses 54, 55, 56, such as ball, convex, etc., maybe utilized. It should further be understood, however, that the presentdisclosure is not limited to the above-described embodiments ofdiplexers 50 and that any suitable diplexers 50 are within the scope andspirit of the present disclosure.

The laser diode 24 and photodiode 16 may be connected, such as directlyconnected, to the diplexer 50. More particularly, the laser diode 24 maybe optically aligned with the diplexer 50, such as with a lens 56thereof. The photodiode 16 may similarly be optically aligned with thediplexer 50, such as with a lens 55 thereof. Visible laser beamsgenerated by the laser source 20 may be transmitted to the diplexer 50from the laser source 20, such as the laser diode 24 thereof, and fromthe diplexer 50 through the first optical fiber 40 to the opticalconnector 30 (and thus to the optical fiber 34). Light (i.e. infraredlight) at a suitable predetermined wavelength(s) generated by opticallight source 36 may be transmitted from the diplexer 50 to the opticalpower meter 12, such as via the photodiode 16.

Referring now in particular to FIGS. 2 and 3, the diplexer 50 mayinclude an optical connector 60, which may be referred to herein as afirst optical connector 60. The diplexer 50 may be coupled to the firstend 42 of the optical fiber 40 through the first optical connector 60.Optical connector 60 may include a body 62 which may extend externallyto and be in contact with the body 58 of the diplexer 50, and the body62 may define an internal channel 64 which extends therethrough and isin communication with an opening 59 defined in the body 58 and whichprovides access to the interior of the diplexer 50.

In some embodiments, as illustrated in FIG. 2, the first opticalconnector 60 may further include a ferrule 66 and an optical fiber stub68 disposed within the ferrule 66. The ferrule 66 and stub 68 may bedisposed at least partially within the internal channel 64, and in someembodiments for example may extend from the internal channel 64 throughthe opening 59 and into the interior of the diplexer 50.

In exemplary embodiments, the optical fiber stub 68 is a multimodeoptical fiber stub 68. In some embodiments, a core of the optical fiberstub 68 may have a standard diameter, i.e. approximately 50 microns.Alternatively, the diameter of the core of the optical fiber stub 68 maybe greater than approximately 50 microns. For example, in someembodiments the core diameter may be approximately 62.5 microns orapproximately 100 microns. While in some embodiments the core diameterof the optical fiber stub 68 may be approximately equal to the corediameter of the optical fiber 40, in alternative embodiments the corediameter of the optical fiber stub 68 may be greater than the corediameter of the optical fiber 40.

Referring again to FIGS. 2 and 3, in exemplary embodiments an opticalfiber connector 70 is provided and coupled to the first end 42 of theoptical fiber 40. The optical fiber connector 70 may couple the firstend 42 of the optical fiber 40 to the first optical connector 60. Inother words, the first optical connector 60 and optical fiber connector70 may connect with each other to couple the first end 42 of the opticalfiber 40 to the diplexer 50.

The optical fiber connector 70 may include a ferrule 72, and the firstend 42 of the optical fiber 40 may be disposed within the ferrule 72. Asshown, the ferrule 72 may be inserted into the first optical connector60, such as into the internal channel 64 thereof. Such insertion maycouple first optical connector 60 and optical fiber connector 70together, and may thus couple the first end of the optical fiber 40 tothe first optical connector 60 and diplexer 50 generally.

In some embodiments, as illustrated in FIG. 3, the first end 42 of theoptical fiber 40 may be exposed when the ferrule 72 is inserted into thefirst optical connector 60. In these embodiments, the first end 42 maynot abut against or otherwise be in contact with any other fibers, andlight may be emitted into the diplexer 50 directly from the first end 42or be received into the first end 42 directly from the diplexer 50. Forexample, in some embodiments as shown, the ferrule 72 may extend withinthe internal channel 64 through the opening 59, such that the first end42 is disposed within the interior of the diplexer 50. The first end 42may, for example, be optically aligned with a lens 54 such that lightemitted from the first end 42 (such as in direction 100) may be directedto the lens 54 and/or light transmitted by the lens 54 (such as indirection 102) is received by the first end 42.

In other embodiments, as illustrated in FIG. 2, the first end 42 of theoptical fiber 40 may abut against the optical fiber stub 68, such as anend thereof, when the ferrule 72 of the optical fiber connector 70 isinserted into the first optical connector 60, such as the internalchannel 64 thereof. Additionally, the ferrule 72 may abut against theferrule 66 when the ferrule 72 of the optical fiber connector 70 isinserted into the first optical connector 60, such as the internalchannel 64 thereof. In these embodiments, light may be emitted into thediplexer 50 from the first end 42 through the optical fiber stub 68, andthus directly from the stub 68, or be received into the first end 42from the diplexer 50 through the optical fiber stub 68, and thusdirectly from the stub 68. The first end 42 may, for example, beoptically aligned with optical fiber stub 68 such that light emittedfrom the first end 42 (such as in direction 100) may be directed intothe optical fiber stub 68 and light emitted from the optical fiber stub68 (such as in direction 102) may be directed into the first end 42.Further, the optical fiber stub 68 may, for example, be opticallyaligned with a lens 54 such that light emitted from the optical fiberstub 68 (such as in direction 100) may be directed to the lens 54 and/orlight transmitted by the lens 54 (such as in direction 102) may bereceived by the optical fiber stub 68.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. An optical fiber test apparatus, comprising: anoptical power meter operable to detect light at a predeterminedwavelength; a laser source operable to generate a visible laser beam; anoptical fiber extending between a first end and a second end; adiplexer, the diplexer comprising a first optical connector and coupledto the optical power meter, the laser source, and the first end of theoptical fiber, the diplexer coupled to the first end of the opticalfiber through the first optical connector; a second optical connectorcoupled to the second end of the optical fiber and comprising a testport; and an optical fiber connector comprising a ferrule, the opticalfiber connector coupled to the first end of the optical fiber with thefirst end of the optical fiber disposed within the ferrule of theoptical fiber connector, the optical fiber connector coupling the firstend of the optical fiber to the first optical connector when the ferruleof the optical fiber connector is inserted into the first opticalconnector, wherein the first optical connector comprises an opticalfiber stub, and wherein the first end of the optical fiber is opticallyaligned with the optical fiber stub when the ferrule of the opticalfiber connector is inserted into the first optical connector, whereinthe diplexer is operable to transmit light at the predeterminedwavelength from the second optical connector to the optical power meterand transmit the visible laser beam from the laser source to the secondoptical connector.
 2. The optical fiber test apparatus of claim 1,wherein the first optical connector comprises a ferrule, and wherein theferrule of the optical fiber connector abuts against the ferrule of thefirst optical connector when the ferrule of the optical fiber connectoris inserted into the first optical connector.
 3. The optical fiber testapparatus of claim 1, wherein the first end of the optical fiber abutsagainst the optical fiber stub when the ferrule of the optical fiberconnector is inserted into the first optical connector.
 4. The opticalfiber test apparatus of claim 1, wherein the optical fiber stub is amultimode optical fiber stub.
 5. The optical fiber test apparatus ofclaim 1, wherein a core of the optical fiber stub has a diameter ofapproximately 50 microns.
 6. The optical fiber test apparatus of claim1, wherein a core of the optical fiber stub has a diameter of greaterthan approximately 50 microns.
 7. The optical fiber test apparatus ofclaim 1, wherein the optical power meter comprises a photodiode.
 8. Theoptical fiber test apparatus of claim 1, wherein the laser sourcecomprises a laser driver circuit and a laser diode.
 9. The optical fibertest apparatus of claim 1 wherein the optical fiber is a multimodeoptical fiber.
 10. The optical fiber test apparatus of claim 1, whereinthe optical fiber is a single mode optical fiber.
 11. The optical fibertest apparatus of claim 1, wherein the diplexer comprises a beamsplitter and a lens optically aligned between the beam splitter and theoptical fiber stub.
 12. The optical fiber test apparatus of claim 1,wherein the first optical connector comprises an internal channel, theoptical fiber stub of the first optical connector extending from theinternal channel and into an interior of the diplexer, and the ferruleof the optical fiber connector is received within the internal channelof the first optical connector when the ferrule of the optical fiberconnector is inserted into the first optical connector.
 13. An opticalfiber test apparatus, comprising: an optical power meter operable todetect light at a predetermined wavelength, the optical power metercomprising a photodiode; a laser source operable to generate a visiblelaser beam, the laser source comprising a laser driver circuit and alaser diode; an optical fiber extending between a first end and a secondend; a diplexer, the diplexer comprising a first optical connector andcoupled to the optical power meter, the laser source, and the first endof the optical fiber, the diplexer coupled to the first end of theoptical fiber through the first optical connector; a second opticalconnector coupled to the second end of the optical fiber and comprisinga test port; and an optical fiber connector comprising a ferrule, theoptical fiber connector coupled to the first end of the optical fiberwith the first end of the optical fiber disposed within the ferrule ofthe optical fiber connector, the optical fiber connector coupling thefirst end of the optical fiber to the first optical connector when theferrule of the optical fiber connector is inserted into the firstoptical connector, wherein the first optical connector comprises anoptical fiber stub, and wherein the first end of the optical fiber isoptically aligned with the optical fiber stub when the ferrule of theoptical fiber connector is inserted into the first optical connector,wherein the diplexer is operable to transmit light at the predeterminedwavelength from the second optical connector to the optical power meterand transmit the visible laser beam from the laser source to the secondoptical connector.
 14. The optical fiber test apparatus of claim 13,wherein the first optical connector comprises a ferrule, and wherein theferrule of the optical fiber connector abuts against the ferrule of thefirst optical connector when the ferrule of the optical fiber connectoris inserted into the first optical connector.
 15. The optical fiber testapparatus of claim 13, wherein the first end of the optical fiber abutsagainst the optical fiber stub when the ferrule of the optical fiberconnector is inserted into the first optical connector.
 16. The opticalfiber test apparatus of claim 13, wherein the optical fiber stub is amultimode optical fiber stub.
 17. The optical fiber test apparatus ofclaim 13, wherein the optical fiber is a multimode optical fiber. 18.The optical fiber test apparatus of claim 13, wherein the optical fiberis a single mode optical fiber.
 19. The optical fiber test apparatus ofclaim 13, wherein the diplexer comprises a beam splitter and a lensoptically aligned between the beam splitter and the optical fiber stub.20. The optical fiber test apparatus of claim 13, wherein the firstoptical connector comprises an internal channel, the optical fiber stubof the first optical connector extending from the internal channel andinto an interior of the diplexer, and the ferrule of the optical fiberconnector is received within the internal channel of the first opticalconnector when the ferrule of the optical fiber connector is insertedinto the first optical connector.